In the domain of XML-based Web applications, sets of XML documents derived from heterogeneous data sources are to be managed. The deployment of XML offers a single and common data model which allows these sets to consider under a data-oriented perspective and to compose their elements to a single, logical XML document. The introduction of a logical representation of the underlying data by a so-called unified view enables comprehensive personalization and customization, because the document structure as well as its graphical presentation can be changed and adapted independently. The intention of this paper is to discuss the idea of building the unified view. Therefore, an overview of the corresponding architecture is given and basic strategies for the building process are presented.